A bank is a financial intermediary that creates credit by lending money to a borrower, thereby creating a corresponding deposit on the bank's balance sheet. Lending activities can be performed either directly or indirectly through capital markets.Banking begins with the first prototype banks of merchants of the ancient world.

Most nations have institutionalized a system known as fractional reserve banking under which banks hold liquid assets equal to only a portion of their current liabilities. In addition to other regulations intended to ensure liquidity, banks are generally subject to minimum capital requirements based on an international set of capital standards, known as the Basel Accords.